This invention relates to a method and system for conditional call forwarding.
Call forwarding features, namely, Call Forwarding No Answer (CFNA), Call Forwarding Busy Line (CFBL), and Call Forward Default (CFD), are commonly available to wireless network subscribers. When invoked, these features permit calls for which a busy or no answer condition has been detected to be automatically transferred to a corresponding voice mail system. Such voice mail systems enable callers to leave voice messages for wireless subscribers when the subscriber has powered off his or her handset, is out of coverage, is engaged in another wireless call, or for whatever reason, elects not to answer the incoming call. The routing to the voice mail systems in all of these conditions is controlled by the above call forwarding features. These features forward all unanswered incoming calls to a single, fixed destinationxe2x80x94a voice mail system.
A prior art wireless communication system is shown in FIG. 1 and designated generally by reference numeral 10. Wireless network 10 includes a Central Office Switch (COS) 12. COS 12 is provided in communication with the Public Switched Telephone Network (PSTN) 14 and one or more subscribers, each having at least one Customer Premises Equipment (CPE) device 16. COS 12 is further provided in communication with a Mobile Switching Center (MSC) 20 and an Intelligent Peripheral (IP) 22. MSC 20 is, in turn, provided in communication with IP 22, a Home Location Register (HLR) 24 and one or more Base Station Controllers (BSCs) 26. Each BSC 26 is provided in communication with one or more Base Stations (BSs) 28. Finally, each BS 28 is provided in communication with one or more mobile handsets 30 each having an assigned calling number known as a Mobile Directory Number (MDN) or Mobile Identification Number (MIN). Each handset 30 also has a preassigned Electronic Serial Number (ESN).
In operation, a call to a mobile subscriber having handset 30 and a preassigned Mobile Directory Number or Mobile Identification Number, whether originated from a wireless network or a wire line network, is forwarded through the Public Switched Telephone Network (PSTN) 14 to COS 12. COS 12 performs a database look-up and identifies the Called Party DN as corresponding to a mobile subscriber. COS 12 forwards the call to the subscriber""s home MSC 20. MSC 20 will thereafter launch a query to HLR 24 requesting the location of handset 30, as well as call termination parameters. This request, termed a Location Request Message (LOCREQ) typically includes information such as calling party identification (the subscriber""s MDN or MIN) and redirecting party identification, the details of which are well known in the art and need not be discussed in further detail here. Thereafter MSC 20 alerts handset 30 by generating a ringing signal.
In an ANSI-41 network, HLR 24 periodically receives update information regarding the location and call parameters for subscriber 30. This typically occurs whenever subscriber 30 xe2x80x9cpowers onxe2x80x9d or enters a wireless serving area and initiates the registration process. Again, as those skilled in the art will recognize, handset 30 detects the presence of a Base Station (BS) 28 or Base Station Controller (BSC) 26. BS 28 or BSC 26, in turn, alerts the serving MSC, here, MSC 20, that the handset 30 has begun registration. MSC 20 thereafter sends a Registration Notification Message (REGNOT) to HLR 24 requesting call termination parameters for handset 30. HLR 24 then sends a Registration Notification Response Message (regnot) to MSC 20. The regnot provides the above referenced call termination parameters for subscriber 30 including whether the party has subscribed to any call forwarding features such as the above referenced CFBL, CFNA or CFD. MSC 20 then stores this information for subsequent processing.
Single number ring services such as U S West One Number Service(trademark), provide a subscribing party the ability to simultaneously receive a ringing signal from a calling party at a plurality of CPE devices. Although each CPE device has a different calling number or DN, a calling party need only dial a xe2x80x9csinglexe2x80x9d calling number or primary number. Each of the subscriber""s DNs for corresponding CPE devices are stored at HLR 24 and cross referenced with the subscriber""s primary number. For example, a subscriber may have a primary calling number of (303) 541-4000 and individual Directory Numbers of (303) 672-2985, (303) 672-2781, and (303) 672-2986 corresponding to the subscriber""s office, home, and mobile telephones, respectively. A calling party, however, need only dial the primary number (303) 541-4000. Using the primary number, COS 12 will perform a database look up and identify the call as directed to a party that has subscribed to one number service. COS 12 will thereafter forward the call to Intelligent Peripheral (IP) 22. IP 22 will launch a query to HLR 24 requesting the specific DNs corresponding to the primary DN. HLR 24 will perform a suitable database look up and provide this information to IP 22 along with the corresponding call termination parameters for each mobile handset 30. IP 22 will thereafter generate and bridge the calls to all of the subscriber""s DNs. Calls to land line or xe2x80x9cwiredxe2x80x9d telephones such as telephone 16 are forwarded over the PSTN 14 to a serving switch such as COS 12 and routed accordingly. Calls to mobile or xe2x80x9cwirelessxe2x80x9d telephones such as handset 30 are forwarded over the wireless network to a serving MSC such as MSC 20.
Regardless if a call to a wireless handset 30 originates from MSC 30 as a direct call, or from IP 22 as part of a one number service product, MSC 20 will initiate a call forward feature if handset 30 is currently engaged in a call or, for any reason, the subscriber fails to answer. This feature sends a Transfer To Number Request Message to HLR 24 requesting further routing instructions. Because HLR 24 is unable to distinguish between calls originating from MSC 20 and calls originating from IP 22, however, all calls will be forwarded to the subscriber""s voice mail system.
As readily seen, forwarding a wireless call to a voice mail system in the case of one number service applications is undesirable, unnecessary, and wasteful of network resources.
Consequently, a need has developed for a method and system for conditionally forwarding calls to a wireless subscriber to an alternative device or system such as a voice mail system upon detection of a busy or no answer condition.
It is a principle object of the present invention to provide a method and system for conditionally forwarding calls to a subscriber to an alternative device or system.
It is a further object of the present invention to provide such a method and system which does not forward calls to a wireless subscriber""s voice mail system when such calls originate from a Mobile Switching Center (MSC).
Still further, it is an object of the present invention to provide such a method and system which does not forward calls to a wireless subscriber""s voice mail system when such calls originate from an Intelligent Peripheral (IP) or are otherwise launched as part of a one number service.
In carrying out the above objects, there is provided a method for conditional call forwarding to an alternative device or system. The method is specifically adapted for use in a communication network including a switching system such as a Mobile Switching Center (MSC) which is provided in communication with at least one alternative system such as, for example, a Voice Messaging System (VMS), and a plurality of subscribers, each having a handset with a corresponding Mobile Directory Number (MDN). The method includes providing a service location register such as a Wireless Service Location Register (WSLR(trademark)) (also called a wireless SCP) in communication with the switching center. The service location register is operative to retrieve stored call termination parameters for each of the subscriber Mobile Directory Numbers and call information for each incoming call to a Mobile Directory Number. The call termination parameters include call forwarding features. The method further includes detecting a busy or no answer condition for a call to a Mobile Directory Number and forwarding a request to the service location register for further routing instructions. The method further includes applying service logic to disconnect the call or route the call to the alternative system.
In a preferred embodiment, the switching system is a Mobile Switching Center (MSC), the at least one alternative system is a Voice Messaging System, and, as indicated above, the Service Location Register is a WSLR(trademark). The call information includes calling party identification and/or redirecting party identification. Further, the request to the WSLRTM comprises a Transfer To Number Request including redirecting reason. The service logic is operative to examine the calling party information and, in particular, the original called number, the calling party identification, redirecting party identification and/or redirecting reason to conditionally determine if voice messaging is applicable. If the call originates from an Intelligent Peripheral therefore indicating that the subscriber""s single number service was invoked, the WSLRTM is operative to instruct the MSC to disconnect the call. In contrast, if it is determined that the call was originally placed to the mobile subscriber directly and not redirected by an IP, the voice messaging destination will be returned to the MSC.
In keeping with the invention, any suitable routing criteria may be provided as part of the call termination parameters. For example, only business related calls as determined by the calling party number or any other suitable information or criteria such as time, day or date of call, etc., may be routed to voice mail. Still further, only calls with unrestricted calling party identification may be routed to voice mail. The subscriber""s Profile as part of the call termination parameters may also provide for routing to multiple voice mail systems in accordance with any suitable criteria such as, for example, business or personal uses.
In carrying out the above method, there is provided a system including an MSC which is provided in communication with a Service Location Register such as a WSLR(trademark), an IP, and a plurality of subscribers and, more particularly, subscriber handsets. The MSC may be provided in direct communication with the handsets or via appropriate base station controllers and/or base stations as known to those skilled in the art. In keeping with the invention, the WSLR(trademark), which is a network computer containing both Home Location Register (HLR) applications and Wireless Service Control Point (WSCP) applications, is operative to retrieve stored call termination parameters for each of the subscribers in accordance with their Mobile Directory Numbers. The WSLR(trademark) is further operative to retrieve call information for each incoming call to a Mobile Directory Number. Call termination parameters include call forwarding features and the call information includes calling party identification and/or redirecting party identification.
The MSC is operative to detect a busy or no answer condition for a call to a directory number and thereafter forward a request such as a transferred to number request to the WSLR(trademark) for routing instructions. In a preferred embodiment, the request includes redirecting reason. The WSLR(trademark) is further adapted to apply service logic to terminate the call at the directory number or forward it to the Voice Messaging System following examination of the call information. Specifically, the WSLR(trademark) will determine if the call originated from the MSC or if it originated from the IP as part of a simultaneous ring service such as the U S West One Number Service(trademark), these and other objects, features, and advantages of the present invention will become readily apparent with reference to the following description of the drawings wherein like reference numerals correspond to like components.